The present invention relates to a method and apparatus for forming discrete batches of tobacco particles, especially for forming elongated sections of an interrupted tobacco stream. More specifically, the invention relates to improvements in a method of and in an apparatus for forming discrete batches of tobacco particles at the periphery of a rotary conveyor, especially a rotary suction wheel.
Tobacco batches which can be formed in accordance with the method of and in the apparatus of the present invention can be utilized to form an interrupted tobacco stream, especially the interrupted core of a composite tobacco filler wherein the core is surrounded by a tubular envelope or shell consisting of a different fibrous material. Such composite fillers can be used for the making of cigarettes, cigarillos, cigars or other rod-shaped articles of the tobacco processing industry.
It is already known to make the fillers of rod-shaped smokers' articles (hereinafter referred to as cigarettes for the sake of simplicity) from several types of natural, substitute or reconstituted tobacco. For example, the core of the composite filler can consist of tobacco particles whose color is different from the color of particles which form the tubular envelope. Alternatively, the core can be made of so-called discard tobacco, namely short tobacco which is removed as surplus from a fully grown tobacco stream and is returned into the distributor of a cigarette rod making machine for reintroduction into the tobacco stream building unit. A drawback of presently known methods and apparatus for the making of such composite tobacco fillers is that they cannot ensure the formation of a satisfactory composite filler at the speed which is required in a modern high-speed cigarette maker, e.g., a cigarette rod making machine of the type known as PROTOS (manufactured and sold by the assignee of the present application) which can turn out up to and well in excess of 8000 plain cigarettes per minute. Moreover, all presently known methods and apparatus for the making of a composite tobacco filler are uneconomical and the quality of the filler is far from satisfactory because the core is not located at the center of the filler, the density of the core is too low and/or the material of the core can be seen at one or both axial ends of each plain cigarette which embodies a portion of such composite filler. A main drawback of presently known apparatus for the making of a composite filler of tobacco particles is that the density of the batches which constitute the core of the composite filler is too low. This is due to the fact that the intervals for accumulation of tobacco shreds into discrete batches of tobacco particles are very short. Thus, if the batches are formed in the peripheral pockets of a rotary wheel-shaped conveyor, satisfactory filling of the pockets in accordance with heretofore known proposals is possible only if the speed of the conveyor is relatively low so that the batches cannot be formed at the rate which is required to form a core for use in a composite filler which is immediately processed in a high-speed maker of cigarettes, cigarillos or like smokers' products.